Drill chuck



March 2, 1948.. J, DONAHUE 2,436,881

DRILL CHUCK Filed Nov. 16, 1945 Inventor 4 Ja A-PH DON Hl/E Patented Mar. 2, i948 iii-y:

UMQTI-EDF- STATES A ENT OFFICE Joseph Donahue, Shamokin, Pa. Application November 16, 1945, Serial No. 629,030

1 Claim. (01. 279-39) This invention relates to a drill chuck, and more particularly to such a'chuck adapted for the holding of drills in drill presses or the like.

A primary object of this invention is to hold broken drills in related assembly with drill chucks, in such manner that they may be readily utilized, even though the shank of the drill has been broken, which breakage normally renders the drill inoperative.

An important feature of this invention is the provision of a special chuck adapted to be seated in a drill press or the like, and having means associated therewith for engaging the flutes or channels in a broken drill, in such manner that the same may be utilized for drilling operation even though its shank may be broken oflf.

An additional feature of the invention is the provision of such a device characterized by a frusto-conical member positioned for movement within a second frusto-conical member, the first member having extended pivoted arms provided with protuberances adapted to engage in the flutes of a broken drill.

A further feature of this invention is the provision of such a device which'will be sturdy and durable in construction, reliable and efiicient in operation, and relatively simple and inexpensive to manufacture, assemble and utilize.

Other objects will in part be obvious, and in part be pointedout as the description of the invention proceeds and shown in the accompanying drawing wherein there is disclosed a preferred embodiment of this inventive concept.

In the drawing:

Figure 1 is a longitudinal sectional view taken through one form of the chuck embodying this inventive concept.

' of. Thelower end of the threaded member l2 Figure 2 i a sectional view taken substantially I along the line 2-2 of Figure 1 as viewed in the direction indicated by the arrows.

Figure 3 is a sectional view taken substantially along the line 33 of Figure 1, as viewed in the direction indicated by the arrows.

Similar reference characters refer to similar parts throughout the several views of the drawing.

Having reference now to the drawing, there is shown at H] a threaded member having a, squared shank ll adapted to engage in a drill press or similar device, the thread of which engage in a threaded aperture l2 in the base l3 of a frusto-conical member l4 having a hollow interior I5, and terminating at its smaller end in an aperture l6, through which a broken drill I1 is adapted to be inserted into the interior thereis provided with a conical depression l8 adapted to engage a conical projection I!) carried on the base of a second frusto-conical member 20 positioned in the recess 15. The member 20 is provided with oppositely disposed cut-away portions 2| within which are pivotally mounted lugs 22 as on pivot pins 23, which lugs comprise inwardly turned ears of arms 24 which extend in opposite aligned relation substantially the full length of the recess IE, it being noted that the member 20 is materially shorter than the longitudinal extent of the recess.

A transverse channel 25 extends across the narrow portion of the member 20 between the arms 24, and contains a tension spring 26 connected to the inner ends of links 21 secured to the arms 24. The lower end of each arm 21 i provided with a hemispherical protuberance 28, the protuberances being oppositely positioned, and adapted to engage in the flutes or channels of the (11111 H. I

From the foregoing the operation of the device should now be readily understandable. When it is desired to utilize a broken drill I1, the shank l I of the chuck is first inserted in the drill press or the like, and the drill passed through the opening l6 between the protuberances 28. R0- tation of the member l3, now causes the same to move upwardly along the threaded portion l0, whereupon the recess l8 engages the conical protuberance I9 on the base of the member 20 forcing the same downwardly within the recess IS in the interior of member l3. Such movement compresses the arms 24 in their associated spherical members 28, which engage in the flutes of the drill I1, the spring 26 assisting in the operation, and holding the drill lightly until such time as the members are firmly seated by the interior configuration of the recess, whereupon when the assembly is tightened the broken drill is held securely in position, and in related assembly with the drill chuck whereby it may be utilized for drilling operations.

4 It will thus be seen that there is herein provided an improved device accomplishing all the pivotally supported upon said pivot pins and having inwardly extending locking protuberances ontheir lower ends adapted to engage in the flutes or channels of a drill when inserted within the 7 open end of said outer member, said inner mem her being formed with a transverse channel in its lower end, inwardly extending arms secured to said clamping arms disposedin said transverse channel, and a coil spring secured between the inner ends of said inwardly extending arms for resiliently urging said clamping arms and protuberances inwardly to positively lock and support a drill when inserted in a chuck.

JOSEPH DONAHUE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 274,135 Morrell Mar, 20, 1883 434,026 Seiders et a1 Aug. 12, 1890 978,208 Reilly Dec. 13, 1910 1,131,990 Bocorselski Mar. 16, 1915 FOREIGN PATENTS Number Country Date 40,698 Germany Sept. 15, 1887 359,810 Germany July 14, 1921 

